Happy birthday, John Tyndall! He was an Irish physicist who first discovered that the daytime sky is blue due to sunlight scattering, now known as the "Tyndall effect." . . . . . . #science #blue #sky #bluesky #tyndalleffect #happybirthday #sciencefacts #physics #particles #skies #blueskies #day #daytime #daylight #nature #earth #atmosphere #irish #ireland